Dust FAQ - Version .2
Folk Lore
of what folks suggested (time's getting the better of me), but there's
still lots to be included. If you have anything to add, particularly
URL's, please send them and I will update accordingly.
Folk...
-------------------------
Dust FAQ v0.2 - 1/24/00
Many thanks go to Gerry Glauser, Jim Thompson, John Lemmons, Bert
Robbins, Brook (DrVermin), Patrick Corrigan, CanoeCedar, Gary Hyde,
Jeff Gorman, Alex Rodriquez, Daniel Shafner and several others for
their informative and professional posts that provided the content for
this FAQ.
Disclaimer: While I have tried to be objective in the writing of this
FAQ, I am human. I started my search for dust collection thinking I
would buy a 650 CFM, then quickly realized a 1200 CFM would be more
appropriate and made the purchase. After more research I realized
that I would not be satisfied with the 1200, back it went, and I
currently have an Oneida on order. There are many woodworkers who
have purchased 650, 1200, and 2000 CFM 'big-bag' dust collectors that
have been very satisfied with them and these systems have served their
needs very well. As this FAQ points out you will need to make your
own determination regarding what is best for your situation. Though I
have tried to be objective, my preferences for perfection may sneak in
occasionally. Please forgive me when this happens.
Q. Why should I include a dust collection system in my shop?
A. There are 4 primary reasons for woodshop dust control:
Health concerns from dust particles - There have been numerous
articles written over the years about the health affects of breathing
various kinds of wood dust, which is now a known carcinogen. I and
many others have worked in woodshops for years with no apparent ill
affects (just as many smoked for years with no apparent ill affects),
however, the mountain of evidence that breathing wood dust is harmful
is growing. Of particular concern are particles of less than 5
microns and especially those less than 1 micron. It should be noted
that adequate measures for health may include dust collection, air
filtration, and/or dust masks.
Cleanliness - Cleaning up sawdust and shavings, especially from a
planer, can be a real pain and can reduce the enjoyment of the work we
are doing. (This is a big plus for becoming a Neanderthal and giving
our $1000 (planer & dust collector) to Tom Lie-Neilson instead).
There's really nothing like stopping every 3 passes through the planer
(when we have 60 passes to do) to clear away the shavings. Further,
dust control may reduce the maintenance on your tools and extend their
life. In some cases a good dust control system can also save your
marriage if you are getting complaints about the beautiful coat of
fine Jarrah on everything in the house.
Sometimes you just need it - For instance, on my router table there
are some operations that I could not perform at all without something
to handle the dust particles, otherwise I would have to stop numerous
times during even some single operations to wipe away the pile. First
option was an air hose, an hour later option (it took me 55 minutes to
go to the store) was a fence-based collector connected to my
wet/dry-vac.
Safety - This is a hotly debated topic, but there is a possibility of
any open flames or sparks creating an explosion, fireball, or fire
from the dust hanging in the air. At this time this appears to be
more theory than reality as there are no known (at least to this
group) documented cases of these types of events in a small or home
shop. This may be akin to saying that sugar is bad for you because
when lab rats were fed twice their weight in sugar on a daily basis
for several years, they died. However, this is a serious problem in
industrial environments and may be a problem in some home environments
so it is included here for completeness and to encourage someone with
authoritative knowledge to step forward.
Q. What types of systems are there?
A. 6:
- Broom and Dust Pan (or for some, just a broom)
Wet/Dry Vac
- Single-Stage Big Bag (currently the most popular, such as the Jet
DC1200-1)
- Two Stage portable (E.G., a canister with a bag on the side)
- Two Stage (Separate chip collector and filter)
- Integral Unit (Blower on top of Cyclone with some type of filtration
such as Oneida)
This FAQ will concentrate on the last 3. It is worth noting at this
point that a dust collection system such as the last 3 operate on
High-Volume, Low-Pressure vs. a wet/dry vac or household vac that
operates on High-Pressure (vac), Low-Volume. There is a reason for
this.
Q. Which one should I buy?
A. This depends on your shop and what you want to accomplish. My
goals are:
- Reduce health problems caused by dust
- Automatically collect most of the dust and shavings from my tools so
I can spend more time making sawdust and less time cleaning it up and
reduce the amount of stuff tracked into the house.
- Easy to empty chip/dust collector
- Quiet (I really don't want the fine high-pitched whine of my planer
disturbed by a loud dust collector)
Your goals may be different and will thus affect the system that you
build or purchase.
Q. What are the CFM ratings I see on the systems?
A. CFM stands for Cubic-Feet-per-Minute and is a measurement of
the volume of air transferred in a given amount of time. For
instance, a home-shop planer generally requires 450 CFM of air
movement to clear away the dust, chips, and other debris. Other
stationary tools need anywhere from 300 to 600. Thus, at first blush
you just need to purchase a dust collector with a CFM rating higher
than your tool with the highest requirements. Not So, CFM by itself
is almost completely useless. You also need to understand a little
about Static Pressure. The CFM ratings on the boxes are often just
the blower, these ratings can be significantly less once filter bags
and any flex or permanent ducting are attached.
Q. What is FPM
A. FPM stands for Feet-Per-Minute and is a measurement of the
velocity (speed) of the air. It is related to CFM, but is different
and important in it's own right, especially if you are installing a
dedicated duct system. You want to insure that you maintain an
airspeed of approximately 4000 FPM in branch circuits and a speed of
3500 in the main duct. The reason for this is that the dust
collection system uses the air-flow to transport the wood chips and
dust from your machine to the collector. Too low a speed and the
chips will no longer stay air-born resulting in chip settlement in
ducts and a fair amount of time on your part un-clogging everything.
For example, you need 450 CFM to clear the debris from your planer. A
4" pipe at at 450 CFM will have a velocity of 3940 FPM. This will
work well. However, if instead you increase the pipe size to 6" your
air velocity will decrease to 2800 FPM. At this rate a relatively
high amount of the heavier particles will not remain suspended and
will settle in the duct causing clog. A good example would be your
outside water hose. With nothing on the end you get a certain volume
of water per minute, usually coming out pretty slow. It wouldn't do
much to wash debris from your driveway. However, if you close down
the end of the hose with your finger or with a nozzle, you will still
get the same amount of volume per minute (CFM), but the velocity or
speed (FPM) at which it comes out is much greater and thus is able to
do a good job of pushing debris from your drive.
The books and references at the end of this FAQ will provide a more
detailed description of this and how to calculate the FPM for your
ducts.
Q. What is Static Pressure or "Inches of Water" ?
A. Static Pressure or SP is a measurement that is married to CFM.
Some people refer to this as the suck power. SP is a way of measuring
and expressing the resistance of all of the components of a dust
collection system. This resistance is caused by several things
including bends in the hose or pipe that the air must move around,
resistance from filter bags, etc. Many dust collectors publish a CFM
figure that is measured at 0" of static pressure or sometimes referred
to as free air flow or free fan flow (and likewise publish a SP number
directly below that is at 0 CFM). Measurements such as these are
misleading. These measurements are for a system with no resistance
whatsoever (which is, BTW, impossible if you actually use the thing).
For instance, a collector might measure 1200 CFM without any pipe or
filter bags connected. As soon as you install the filter bags the CFM
drops to about 1050 (for standard sized 30 micron bags, approximately
800 CFM for 5 micron and 600 CFM for 1 micron). 4" flex hose has a
static pressure of anywhere between 0.157" to .210" per linear foot.
Thus, if you add 10' of flex hose between your dust collector and
Planer you've added approximately 2" of SP and again reduce your CFM.
Now you're down to approximately 600 CFM at your tool (assuming 5
micron bags). . An accurate measurement will be indicated as xx CFM @
xx" SP such as 560 CFM @ 7.62" SP.
So, to know the performance of the dust collector you need to know
what the CFM is at a given static pressure. This is often referred to
as the performance curve. Following are some performance curve
numbers for a typical single-stage, big-bag system. These numbers are
for just the blower and do not include filter bags or ducting.
(disclaimer: These measurements were produced quickly and are only
psuedo scientific, but they do come very close to the numbers provided
by the manufacturers*).
1.5hp / 1200 cfm
CFM SP
1200 1.96
800 4.01
400 6.65
200 7.5
100 8.2
0 11
2hp / 1500 cfm
CFM SP
1500 .21
1200 2.22
800 4.2
400 7.63
200 8.79
100 9.33
0 11
3hp / 2000
CFM SP
2000 3.91
1500 4.18
1200 6.72
800 8.45
400 10.11
200 10.89
100 11.43
0 12.57
Oneida 1.5hp integral cyclone/dust collector:
CFM SP
750 8"
* Though most manufacturers don't openly publish their performance
curve information yet, all but one provided the information to me over
the phone once I got them to think I actually knew what I was talking
about. Since most people do not understand this information I can
understand their hesitancy in openly publishing these numbers since
many people might try to compare A's 800 CFM @ 8" SP with B's 1200 CFM
at 0" SP and incorrectly determine that B is better. Ok, done with my
defense of manufacturers for the year.
Q. How do I know what my CFM and SP requirements are (remember,
FPM should always be approximately 4000 in the branches and 3500 in
the main duct)?
A. This depends on several factors. You need to start with your
tool and determine what the CFM requirement for your tool is (it will
not have a SP requirement). Then add up all of the SP values from
your tool to your dust collector. Then add any correction factors for
filters, etc.
Some typical tool requirements are:
TS 350 - 600 (larger blades, faster ripping, or dado's
require higher CFM)
Bandsaw 400
Jointer 350
Planer 450
Mitre Saw 300
Router Table 350
For a simple system, such as when you plan to drag a flex hose and/or
collector to each tool individually, you can start with the tool with
the highest requirement such as a Planer that requires 450 CFM. Add
1" SP for the dust hood, 0.18" per foot of flex ducting (say 12'), and
1" for filter bags. This will give you a static pressure for the duct
system of 4.16" (of water). Thus you need a system that can deliver a
minimum of 450 CFM @ 4.16" SP. The 1200 CFM unit above will meet this
requirement (a 650 CFM unit may fall short). But, if you decide to go
with 5 micron bags (highly recommended) instead of 30 micron, you will
reduce the CFM by approximately 30%. So at 4.01" SP (close to what we
need) you will get 560 CFM, which should still be close enough (since
4.01" SP is less than the 4.16" we need then we will need a slightly
higher CFM to compensate, but since we have 110 extra CFM we should be
OK).
If you get tired of emptying the bags and cleaning chips from the
impeller (blower) you will probably add some type of chip separator.
This will increase your SP by anywhere from 1" to 3" (depending on
design) and may put you in a position of moving up to a 1500 or 1900
CFM unit.
If, on the other hand you decide to install permanent ducting, you
will need to calculate your SP for the highest resistance run in your
system. My worst run is to my TS:
Feet Dia " Desc Factor SP"
1 Hood 1 1
4 5 Flex Duct 0.165 0.66
6 5 Pipe 0.055 0.33
4 5 Flex 0.165 0.66
3 5 Pipe 0.055 0.165
9 5 90 deg 0.055 0.495
10 5 Vertical Rise 0.055 0.55
9 5 90 deg 0.055 0.495
28 6 Main 0.035 0.98
1 6 Flex 0.165 0.165
1 Cyclone 1 1
13 7 90 deg 0.026 0.338
13 7 90 deg 0.026 0.338
8 7 Vert 0.026 0.208
13 7 90 deg 0.026 0.338
1 Filter Loss 1 1
Total 8.722" SP
Thus, I need 500 CFM @ 6.5" SP at the cyclone entrance or 500 CFM @
8.8" SP at the dust collector. A 2hp/1500 unit would be close, but
still fall under a bit, so I'd have to look at a 3hp/2000CFM unit if I
go with this approach.
Oneida and Air-Handling systems (URL's below) both provide some good
information on designing systems and calculating SP".
After all of my research, I've determined that the Onieda 1.5hp
integral system is the best option for me (and probably for anyone
concerned about the health aspects of fine dust). No other
combination of units can provide the same filtration from a health
standpoint at anywhere near the $650 cost of the Oneida. The Oneida
also takes up a 2' x 2' floor space which is significantly less than
any other option. It is possible to meet the second requirement of
just chip collection (eg, we don't care about our health) for less
money, especially if we don't mind building some stuff ourselves,
emptying bags instead of cans, and/or dragging flex duct to each tool
each time we use them. If you only use power tools occasionally, you
can probably get by with a 1200 CFM DC, 5 micron bags, and maybe a
garbage can cyclone (from Veritas) or homemade chip collector for less
than $350. Some people have also purchased 650CFM systems and been
happy with the chip collection. It will really come down to what you
are trying to accomplish.
Q. How can the Oneida integrated cyclone/filter work without
those big attractive filter bags?
A. The design of the filter cartridge on the Oneida provides for
a large surface area without large volume. Keep in mind that with the
'big bag' type systems most of the bag volume is unused, especially if
you have a chip collector. Since the 1st stage chip collector gets
everything but the really fine dust, all you really need is filter
surface area and enough air space to carry the air to the filter
surface and distribute it evenly. For instance, on the big bag
systems, you could flatten the bags down to about 2" - 4" inside
airspace and everything would work as well (OK, almost as well, you
need something to distribute the air evenly across the surface area).
Also, the cyclone on the Oneida is efficient enough to remove a large
portion of the dust prior to the filter, so what does make it to the
filter already has a fairly low dust content, thus extending the time
between cleanings.
Q. Is plastic pipe OK for ducting?
A. This has been a subject of much debate. Personally I don't
believe the cost of metal is enough over plastic to make it an issue
for me (depending on where you buy what). All commercial shop systems
utilize spiral metal pipe. Many people prefer plastic since it is
less expensive, easier to put together, and generally more available
at local stores. However, plastic does require a ground wire either
inside or out to eliminate static electricity which lessens the 'ease
of install' element. If you do choose plastic, make sure that you get
a large enough inside diameter and that the wall thickness is
appropriate for the system you are installing.
Q. My local store sells a nice looking line of tools including a
dust collection system. The dust system includes some cool looking 2"
clear plastic pipe and has connectors for each of their tools. Is
this a good choice?
A. I cannot find anybody who would recommend 2" pipe for dust
collection on anything more than a small carving tool or some hand
tools connected to shop-vacs. This type of system is completely
inadequate for any stationary tools.
Q. Where can I find plans to build my own Cyclone?
A. Wood Magazine ran an article in Dec '98 covering this. Penn
State has a package of the components here:
http://www.pennstateind.com/cyclon2.html. Also check the Winter 1999
issue, # 120 of Wood magazine for an update to the design.
Also, http://members.aol.com/woodmiser1/dust.htm has a unit that looks
pretty good.
Two critical things to keep in mind when building your own are to make
sure that you use a strong enough metal to avoid collapse from the
negative air pressure and make sure your collector is dimensioned
properly. DrVermin posted the following a while back concerning some
basic dimensions:
A: The diameter of the top of the cyclone; i.e. the part that is not
tapered.
B: The diameter of the pipe coming out of the top of the cyclone; i.e.
the outlet.
C: The diameter of the pipe coming in to the cyclone: i.e. the inlet.
D: The diameter of the opening at the bottom of the cyclone where the
chips and solids fall into a bin.
E: The vertical distance from the top of the outlet pipe to the top of
the untapered part of the cyclone.
F: The vertical height of the top (untapered part) of the cyclone.
G: The vertical height of the tapered part of the cyclone.
Actual Dimensions (inches)
CFM HP A B C D E F G
350-550 1 16 6 4 6 5 16
18.5
550-800 2 18 7 6 7 5 18
20.5
900-1200 3 21 8 7 8 5 21 24.5
Q. How can I connect a dust collector up to my contractors table
saw?
A. Some manufacturers make kits for their saws that do a good
job. Others either don't have the kits or what they have is not worth
a whole lot. Best option is to connect a 4" - 6" duct to the bottom
of the saw with either a manufactured or shop-made plate. Then seal
up the back side of the housing as best you can. Make sure that
whatever you do on the back allows for free movement of the motor and
drive belts. Some people have found that making various plates out of
foam or plywood with magnets for attaching to the cabinet have worked
well. One thing to remember is that you don't want to completely seal
this opening up, the slit in your table insert is fairly small,
especially if you use 0 clearance inserts and the dust collector needs
to draw enough air to keep the sawdust suspended, so it will need to
draw some air through the back or elsewhere. After all of this you
should also look at a second pickup attached over the blade since an
under-cabinet arrangement will not be able to get everything.
Integrated bladeguard/dust ports are the best option and can be
purchased or made.
Q. How can I connect a dust collector up to my bandsaw?
A. Some manufacturers make kits for their saws that do a good
job. Others either don't have the kits or what they have is'nt worth
a whole lot. Various people on this group have tried various ways to
attacking this problem with differing results. The generally
recommended approach is to utilize two ducts, one connected to the
lower wheel housing and the other just below the table near the lower
guides.
Q. The dust port on my xxxx is 2 ¼" or 2 ½", where can I find
fittings to connect this to my system?
A.
Q. I want to connect micro-switches to my blast gates to turn the
collector on automatically, where can I find information on doing
this.
A. First, I would recommend using the magnetic door/window
sensors used in an alarm system instead. These will not have the
dust/clog problems of typical micro-switches. Attach the magnetic (no
wires) portion to the blast gate itself and the wired portion so that
it is in contact (or close) with the magnet when the gate is either
open or closed (your choice). These switches are available as
normally open (NO) and normally closed (NC) depending on how you want
to wire your system. (NO) are the most common for alarm systems.
Q. Should I purchase or make one of the ceiling mount
air-filtration systems like the JDS 2000?
A. Depends. If you purchase a system such as the Oneida integral
dust collector/cyclone, you MAY not need a separate air filtration
unit unless you do a lot of sanding with tools not connected to your
DC. Also, if you place your DC system in a sealed room/closet with
sub-micron filters such as 3M Filtrete filtering the air as it
reenters the room (or you exhaust the air and bring in fresh somewhere
else), you may not need a separate unit. If you don't do either of
these and you do create dust, you should probably consider a good
air-filtration system. JDS, Delta, Jet, and others make these units
and they are also fairly easy to build.
Q. The filter on my wet/dry vac is always getting clogged from
fine woodworking dust, what can I do?
A. First, you should invest in a 'CleanStream" filter which is
much better than the paper filters normally included with wet/dry vacs
and has more surface area. These are available from several warehouse
places and from most online/catalog woodworking shops. Second, you
can stretch some pantyhose over the filter. This will slow down the
clogging so that you clean it less often. Don't forget to
remove/replace this each time you clean the filter.
Q. What can I do with all of the shavings and sawdust?
A. Some common uses are both mulch and compost in the garden and
as a bedding for animals, particularly horses. In either of these
cases however you must be EXTREMELY careful about what you have. Some
woods and most chemicals (glue, etc.) can very detrimental to some
plants and animals. If you're not sure, you should throw it out in
the trash (unless local regulations don't permit this). Pressure
treated lumber dust should always be tossed. Jeff Gorman's page
http://www.millard.demon.co.uk/Shavings.htm has some interesting
thoughts on this.
Q. Once I have a dust collection system will I still need to wear
a dust mask?
A. For certain operations you should definitely were a dust mask
even when you have the best dust collection and air filtration system
in the world. Anytime you're sanding, cutting MDF or similar
materials, or applying finish are good times to consider a mask.
Also, if your dust collection system does not filter down to at least
1 micron or below you should consider wearing a mask anytime you are
creating dust of any sort. The collector may suck up everything from
the work you are doing, but the stuff below the size of your filters
capability will be spewed all over your shop, sometimes creating a
worse health hazard than if you had no dust collection at all.
Investment in a good mask with replaceable filter cartridges is worth
the money. They're not exactly a fashion statement, but then again,
if you're wearing a good pair of safety glasses then this issue's
already out the window anyway. 3M is generally considered the leader
in this field for both commercial and hobby with their 6000 series.
You can also try the Dust Be Gone mask - http://www.dustbeegone.com
Be careful what kind of filters the mask has on it initially. Many
come standard with 'chemical' filters which should be exchanged for
dust filters. Put the chemical filters in a sealed baggy so they're
ready to use when you spray something. Don't forget to clean/change
the filters occasionally and check the purge valve as well. Also note
that some chemical filters have a short life once they have been
exposed to air. This life can be as short as 2 hours.
From the Newsgroup:
DustFoe 88 - About $30 from http://www.highlandhardware.com
Lightweight, won't fog glasses, rubber seal, and has replaceable
filters. Available from Highland Hardware in Atlanta for $25-$30.
This also works well for people with beards. The mask works for dust
only, not fumes.
Racal Power-Visor - About $160 from
http://www.http://envirosafetyproducts.com
3M #6000 series half or full face respirators. It is one of the few
full face masks that cannot fog. This is because the design of this
very comfortable mask separates the breathing part from the face
sheild part. You can get dust filters for this so that you don't hav
to use your filter cartridges (these cartridges do have a shelf life
once they have been exposed to air, and that life is very short,
perhaps 8 to 12 hours of exposure). If you do get this full face
mask, be sure to purchase the lens sheild covers that are available.
These are clear plastic sheilds that fit right onto the lens of the
mask. Replacing the lens is expensive should it get scratched. These
lens covers are not.
The mask is about $100. It is as comfortable as any mask that you
could ever put on. The filters and cartridges are all compatible with
the 6000 series half mask respirator (3M's Easy Care). And both of
these
respirators allow for easy hook up to a positive feed fresh air
supply. Just hook the hose with a compatible fitting to where you
would normally fit the cartridges onto.
This full face respirator is so much more effective than those white
dust masks. Like it or not, saw dust is a carcinogen. And the
industrial asthma that you can get from exposure to saw dust is not
curable, and it
does not go away.
Q. How can I keep from fogging up my safety glasses when I'm
wearing a dust mask?
A. In general a good mask that seals around your face well and
has replaceable filter cartridges will eliminate problems with
fogging. Other options include; 1) Anti-fog juice (available from
scuba shops and some auto supply places) or 2) Spit (yep, that fine
stuff from your mouth. Spit on the inside of the lens and wipe it
around (don't dry it). This will almost always work.
Also, to reduce and/or eliminate dust cling to the outside you can try
wiping your lenses with anti-cling dryer sheets. There are rumors
that this also works well for the dust shoots on jointers and other
tools.
Other Resources (There are many others, but these will get you
started):
Books:
Woodshop Dust Control - Sandor Nagyszalanczy - ISBN: 1-56158-116-X
Must visit:
http://www.jimthompson.net/family/dust%20collection.htm
http://www.oneida-air.com
Manufacturers:
http://www.airhand.com
http://www.oneida-air.com
http://www.jettools.com
http://www.pennstateind.com
http://www.deltawoodworking.com
Cyclone - Design & Build
Principles:
http://www.wsu.edu:8080/~gmhyde/433_web_pages/cyclones/-CycloneOverview.html
Home-Made Collector: http://members.aol.com/woodmiser1/dust.htm
Parts for Build Your Own: http://www.pennstateind.com/cyclon2.html
Gerry Glauser
imagine what you would have produced with more of it. IMO, that's the
best written and most comprehensive introductory treatment that I've
seen, and you've put some books to shame. There are only two things I
can think of adding.
First, finding a vendor with a range of cheap adapters to get from here
to there. I notice you left that blank, and I do understand why. I
really wish I could add something here.
Second, dust hoods and directors. That's an approach that has received
little mention anywhere, and deals with localized control of fine dust.
For instance, a scroll saw produces a fair amount of very fine dust, and
the blower that keeps your work clear also serves to bring some of this
airborne. Since you're sitting in front of it, none of the methods here
will help, and some are too noisy to consider. As the concern is not the
heavy dust that settles but the airborne component, a shroud can be
placed behind the saw with angled sections to direct the air, and two
very quite (and very cheap) whisper fans (like those in PC's) added,
with simple filters. A similar approach can be used for stationary belt
sanders and anything that produces fine dust that can't be easily
contained. A small portable version built with plywood can be moved
around as needed. The filters need not catch all the dust, but will at
least get it away from you.
--Gerry Glauser
On 1 Feb 2000 13:02:45 -0600, Folk Lore <folk...@nospam.net> wrote:
>Here's the second and semi-final version of the Dust FAQ. Added some
>of what folks suggested (time's getting the better of me), but there's
>still lots to be included. If you have anything to add, particularly
>URL's, please send them and I will update accordingly.
>
>Folk...
>
>-------------------------
>
>Dust FAQ v0.2 - 1/24/00
>
<snip>
John Huffman
The reference to 2" clear plastic fittings sounds a lot like HD and the
Ridgid stuff. I wonder how many poor souls have installed this and
found out why it's clear, because it is always clogging up!
My only comment of substance is that my experience with magnetic
switches has been dismal and I've replaced them with micro switches. It
may be that the ones I used were abnormally weak, but too often I would
come out to the shop to find the DC running and I'd track the problem
down to a gate that was just on the borderline of keeping the circuit
closed. Also, any splinters that lodge in the back of the gate may
increase the distance between the magnet and the switch when you shut
the gate and this leads to possible loss of contact. I have not had the
micro switches foul as of yet (about 1 year). I attached them with hot
melt glue so they're easy to replace if needed.
Folk Lore
typed on his/her/it's keyboard:
>Very impressive and thanks for the effort of doing this for all to use.
Thanks!
>The reference to 2" clear plastic fittings sounds a lot like HD and the
>Ridgid stuff. I wonder how many poor souls have installed this and
>found out why it's clear, because it is always clogging up!
Yep. I have to admit I'm a bit guilty of going in HD for stuff and
venturing by the Rigid section to get some advice on my new dust
collection system. Did you know that this is the type system "that
all the pro's use"? Well, the Rigid rep happened to be in the store
one day and informed me of that. Education is always good.
>My only comment of substance is that my experience with magnetic
>switches has been dismal and I've replaced them with micro switches. It
>may be that the ones I used were abnormally weak, but too often I would
>come out to the shop to find the DC running and I'd track the problem
>down to a gate that was just on the borderline of keeping the circuit
>closed. Also, any splinters that lodge in the back of the gate may
>increase the distance between the magnet and the switch when you shut
>the gate and this leads to possible loss of contact. I have not had the
>micro switches foul as of yet (about 1 year). I attached them with hot
>melt glue so they're easy to replace if needed.
Good to know. I think there are various types of magnetics. The ones
I use are NO (and are mounted on the top of the gate, not bottom), but
close when the magnet is anywhere within about 1.5" of the face.
What mfr micro are you using?
Folk Lore
typed on his/her/it's keyboard:
>If time's getting the better of you, then it's rather difficult to
>imagine what you would have produced with more of it. IMO, that's the
>best written and most comprehensive introductory treatment that I've
>seen, and you've put some books to shame. There are only two things I
>can think of adding.
Nothing like a bit of encouragement to keep going...
>First, finding a vendor with a range of cheap adapters to get from here
>to there. I notice you left that blank, and I do understand why. I
>really wish I could add something here.
Me too. I know there's some stuff out there other than duct tape, I
just haven't run across it yet.
>Second, dust hoods and directors. That's an approach that has received
>little mention anywhere, and deals with localized control of fine dust.
>For instance, a scroll saw produces a fair amount of very fine dust, and
>the blower that keeps your work clear also serves to bring some of this
>airborne. Since you're sitting in front of it, none of the methods here
>will help, and some are too noisy to consider. As the concern is not the
>heavy dust that settles but the airborne component, a shroud can be
>placed behind the saw with angled sections to direct the air, and two
>very quite (and very cheap) whisper fans (like those in PC's) added,
>with simple filters. A similar approach can be used for stationary belt
>sanders and anything that produces fine dust that can't be easily
>contained. A small portable version built with plywood can be moved
>around as needed. The filters need not catch all the dust, but will at
>least get it away from you.
Great point! Adding now.
Thanks,
Folk...
Mark N Katz
Folk Lore (folk...@nospam.net) wrote:
: Here's the second and semi-final version of the Dust FAQ. Added some
: of what folks suggested (time's getting the better of me), but there's
: still lots to be included. If you have anything to add, particularly
: URL's, please send them and I will update accordingly.
Good job.
A nit-picking correction:
: Must visit:
: http://www.jimthompson.net/family/dust%20collection.htm
didn't work for me but:
http://www.jimthompson.net/family/dustcollection.htm
did.
Mark
lb10
Glauser <ger...@cisco.com> wrote:
>Second, dust hoods and directors. That's an approach that has
received
>little mention anywhere, and deals with localized control of
fine dust.
>For instance, a scroll saw produces a fair amount of very fine
dust, and
I'm speaking only from theory, so correct any incorrect
statements.
When using a DC near a scroll saw (or other tool used with small
pieces of wood), place a screen over the DC inlet at the tool so
you don't lose that small piece. The screen needs to be large
enough so as not to restrict the flow of air (and dust), but not
so large as to allow your work piece to disappear before your
eyes.
BTW Folk Lore, Do you have a web site for your FAQ? I would
like to be able to bookmark it for future reference. Like when
I get more serious about buying/building a DC (translation: get
the approval from the boss and the money).
- les
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John Huffman
>
I'd have to look close for a name, but I bought them from WW Grainger.
They have a soft steel trip lever that can be bent easily so that the
switch engages in the correct range when the blast gate handle touches
it upon closure. I used NO switches as well but in reality they are
normally closed by the blast gate handle to create a continuous circuit
among all of my machines. OPening any one switch breaks the circuit
which activates a NC type relay (also bought from Grainger). A cheap
24v DC power supply activates the circuit. My main fear was that any
break in the circuit starts the DC, but since my switch problem was
fixed, this has never happened. I don't think I have more the $50 in
this whole thing for about 7 machines. Again thanx for the FAQ.
Folk Lore
typed on his/her/it's keyboard:
>A nit-picking correction:
>
>: Must visit:
>: http://www.jimthompson.net/family/dust%20collection.htm
>
>didn't work for me but:
>
> http://www.jimthompson.net/family/dustcollection.htm
>
>did.
ATTN: Jim Thompson YOU CHANGED YOUR URL !!
Thanks,
Folk.
Folk Lore
<lbartel...@undergraph.com.invalid> typed on his/her/it's
keyboard:
>When using a DC near a scroll saw (or other tool used with small
>pieces of wood), place a screen over the DC inlet at the tool so
>you don't lose that small piece. The screen needs to be large
>enough so as not to restrict the flow of air (and dust), but not
>so large as to allow your work piece to disappear before your
>eyes.
Yep, kinda important. Added.
>BTW Folk Lore, Do you have a web site for your FAQ? I would
>like to be able to bookmark it for future reference. Like when
>I get more serious about buying/building a DC (translation: get
>the approval from the boss and the money).
Nope.